Analysis of factors influencing pancreatic beta-cell function in Japanese patients with type 2 diabetes: association with body mass index and duration of diabetic exposure.
OBJECTIVE
To elucidate the clinical factors affecting beta-cell function, serum C-peptide immunoreactivity (CPR) levels of patients with type 2 diabetes were analyzed.


METHODS
Seven hundred Japanese patients with type 2 diabetes were enrolled. beta-Cell function was evaluated by fasting CPR (FCPR), 6 min after intravenous injection of 1mg glucagon (CPR-6 min), and the increment of CPR (DeltaCPR). Simple regression analysis between FCPR, CPR-6 min, and DeltaCPR and measures of variables and stepwise multiple regression analysis were carried out.


RESULTS
Years from diagnosis and BMI were the major independent variables predicting beta-cell function. Years from diagnosis was negatively correlated with CPR-6 min (P<0.0001, r=-0.271), and decrease in CPR-6 min was 0.050 ng/(ml year). BMI was positively correlated with CPR-6 min (P<0.0001, r=0.369). When subjects were divided according to BMI, the decrease in CPR-6 min per year in the high-BMI group (0.068 ng/(ml year)) was greater than that in the low-BMI group (0.035 ng/(ml year)).


CONCLUSIONS
A linear decline in endogenous insulin secretion over more than several decades of diabetes was confirmed by this cross-sectional study. The duration of diabetes exposure and BMI are thus major factors in beta-cell function in Japanese patients with type 2 diabetes.
Funakoshi
Shogo
S
Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
Fujimoto
Shimpei
S
Hamasaki
Akihiro
A
Fujiwara
Hideya
H
Fujita
Yoshihito
Y
Ikeda
Kaori
K
Hamamoto
Yoshiyuki
Y
Hosokawa
Masaya
M
Seino
Yutaka
Y
Inagaki
Nobuya
N
D044466:Asian People; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000473:pathology*; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism* / Q000502:physiology; D008875:Middle Aged; D012044:Regression Analysis; D013997:Time Factors
D002096:C-Peptide; D007328:Insulin